1. Field of the Invention
The present invention relates to a field electron emission source.
2. Discussion of Related Art
Field emission displays (FEDs) are relatively new, rapidly developing flat panel display technologies. FEDs are based on emission of electrons in a vacuum, and light emitted by electrons emitted from micron-sized tips in a strong electric field, accelerating, and colliding with a fluorescent material. FEDs are thin and light with high brightness. Compared to conventional technologies, e.g., cathode-ray tube (CRT) and liquid crystal display (LCD) technologies, FEDs are superior in having a wider viewing angle, lower energy consumption, a smaller size, and a higher quality display. A field electron emission source is an essential component in the FEDs.
The field electron emission source operates in a vacuum environment, where an electrical field is applied to the emitters to generate electrons. The emitters are connected to a cathode electrode. A positive gate extracts electrons from the emitters through a vacuum gap. In order for emission to occur, a strong electric field is required. A high field emission efficiency can be achieved by sharpening the emitters to a high aspect ratio and by lowering a distance between the emitters and the gate.
The widest known field emission electron source is the Spindt-type field emitter, which uses a conical or pyramid micro-tip closer to the gate as emitter. However, a current leakage is possible between the emitter and the gate, which prevents a wide application thereof. Recently, various nano-structures, such as nanotubes and nano-wire, have been successfully synthesized. They have a high aspect ratio. However, the field emission electron source having nano-structures has low stability. Further, because distances between adjacent nano-structures is small, a strong shielding effect is produced, lowering the field emission efficiency.
What is needed, therefore, is a field electron emission source with high field electron emission efficiency, high stability, and low current leakage, and a method for manufacturing the field electron emission source.